The present invention relates to open mouth bags which may be used in existing automatic bag filling processes, and more particularly to an improved construction of a bag for use in a wicketed assembly or assembly of bags which provides improved automatic filling of articles such as vegetables and fruit, e.g., potatoes, apples, oranges, cherries and the like into an open mouth bag.
Bags constructed of thermoplastic material, such as polyethylene, polypropylene, etc., are generally made by cutting through a strip of double-ply material at successive intervals by means of a heat knife, wire or the like, which simultaneously cuts through and heat-seals the cut edges of the overlying plys together. These bags are ordinarily difficult to open because the walls of the bag tend to adhere to each other. This is an especially disadvantageous feature when the bags are used in commercial production where they must be easily opened by automated bag filling equipment in order to make automated processes feasible.
In automated bag filling equipment, the bags often are mounted in large numbers or assemblies on wickets, clamps or other devices that allow the bagging system to access the bags. In a typical bagging system each bag is opened individually and filled with a product. One example of this type of automatic equipment is disclosed in Germunson et al., U.S. Pat. No. 3,822,527. Germunson discloses an automated bagging system that opens a wicketed assembly of bags using a jet of air followed by the insertion of a scoop. The wicketed assembly of bags is positioned at the end of a chute, down which measured amounts of fruits or other material are fed. The initial jet of high pressure air blows the bag open so that a scoop can enter the bag and support the bag edges to provide a wide opening for the fruit to enter the open bag.
Several drawbacks exist in prior automated bagging systems. In particular, the blast of air does not always open the bag completely. During the bagging process the spatial relationship between the lip of the top bag and air jet changes as the bags are used. If the air is correctly aligned to open the bag when a new assembly of bags is placed on the machine, this alignment may not be correct for the jet of air to open the bags that are located deeper in the assembly. As a result it is not unusual for the operator to have to watch the bags as they are opened and to have to assist manually in opening the bags on some occasions.
It has been now found that the difficulties noted above can be overcome by the simple but highly effective operation of providing preformed cuts at each side of the bag, which are horizontally aligned with, but off-set from the lip of the bag opening. The cuts allow jets of air directed into the bag to easily and reliably inflate the bags so that the scoops can be inserted.
According to the present invention a bag for use on automated bagging equipment is provided wherein the bag comprises:
a back panel having a top edge, a bottom edge and first and second side edges; and
a front panel having a top edge, a bottom edge and first and second side edges, the back panel being longer than the front panel, wherein the back panel includes a tear line which runs parallel to the top and bottom edges of the back panel and extends between the side edges thereof, the tear line including a middle portion which is perforated and two lateral portions which are cut and intersect the side edges of said back panel, the front panel being juxtaposed with the back panel such that the side edges and the bottom edges are contiguous, the front panel being joined to the back panel along their corresponding side edges and bottom edges.
The present invention also provides an assembly of bags wherein each bag has the structure identified above.
The invention also provides an improved automatic bagging method for opening and filling a bag in a wicketed assembly of bags with a product including the sequential steps of automatically:
inflating each bag in the wicketed assembly of bags with air;
holding the inflated bag open with a pair of spreader arms;
filling the inflated bag with the product; and
detaching the filled bag from the assembly, the improvement wherein the wicketed assembly includes a plurality of bags wherein each bag comprises:
a back panel having a top edge, a bottom edge and first and second side edges; and
a front panel having a top edge, a bottom edge and first and second side edges, the back panel being longer than the front panel, wherein the back panel includes a tear line which runs parallel to the top and bottom edges of the back panel and extends between the side edges thereof, the tear line including a middle portion which is perforated and two lateral portions which are cut and intersect the side edges of the back panel, the front panel being juxtaposed with the back panel such that the side edges and the bottom edges are contiguous, the front panel being joined to the back panel along their corresponding side edges and bottom edges.